Aligning CAD dwg with Revit model

[Anonymous]

I have a Revit model of a building that I'm preparing for a client. I have also been given a CAD DWG file which has the locations of control points around the building and I need to import this to the correct location relative to the building.

When I open the model as an IFC file in Trimble Business Centre and import the CAD file on top of it, it imports in the correct position automatically, but attempting the import in Revit gives me a result that is completely at the wrong elevation in the 3d view , no matter what import option I use. 

I can probably manually reposition this but was wondering if there is a quicker procedure to import the DWG into Revit correctly. Thanks. 

[ryley.g.h]

It depends on the CAD file really. See the attached image. First, the CAD origin will snap to the Revit origin, so if the CAD origin is set at 0 z (Typical 2D drawings are by default), but your revit is 300 z (floor level), it will be 300 below your Revit. You can try inserting at different levels, which should override the z value of the origin.

Alternatively, insert it and just unpin, then move the CAD file in 3D, then re-pin it.

[Anonymous]

Hi, thanks for the reply. Yes, I suppose that manual re-positioning is what I'd have to do, but I can't understand what TBC is doing to get the DWG onto the 3D model in the right location with minimal user intervention vs. why Revit seems to have trouble with it. 

[SteveKStafford]

The number one issue with DWG files is extents. If you get a message regarding the "size of the file and Revit using Center to Center instead" (paraphrasing) then it has extent issues.

For it to work in Trimble that suggests some sort of "coordination" exists between where the model is and what the source DWG file is. That could just be the origin of both files is the "same"...a grid intersection for example is the same. If you link such a DWG using origin to origin it ought to land in the right place...unless the first paragraph is true.